A 634.5 g sample of helium absorbs 125.7 calories of heat. The specific heat capacity of helium is 1.241 cal/(g·°C). By how much did the temperature of this sample change, in degrees Celsius?

Answer:

Limiting Reagent = Aluminum

Mass formed = 28.92g (4.s.f.)

Explanation:

Step 1: Write a balanced equation for the reaction

We know that Aluminum hydride is formed from hydrogen and aluminum, so we can put those elements in our equation first:

H2 + Al -> AlH3

*Remember that hydrogen is a diatomic molecule so it is H2.

Now let's balance it! We can see that the Al molecules are balanced but the Hydrogens are not, so we can multiply both molecules by the opposite number:

3H2 + Al -> 2AlH3

Now we have 6 hydrogens on each side, we just add a 2 to balance the aluminum and we have the balanced equation!

3H2 + 2Al -> 2AlH3

Step 2: Convert all values to no. of moles

To do this, we can use the formula:

mass = no. moles x Molar mass

Which we can rearrange to find No. moles = mass/ Molar mass

Hydrogen: 3.00/2.02 = 1.49 moles

Aluminum: 26.00/26.98 = 0.9637 moles

Step 3: Find the Limiting Reagent

Now we choose one (let's use hydrogen) and divide by the co-efficient ratio between the two elements (3H2 for every 2 Al).

1.49 x 2/3 = 0.993 (This is the theoretical amount of Aluminum we need for the amount of hydrogen we have)

Now we compare this number with the actual no. moles of aluminum we have to find the limiting reagent:

0.993 > 0.9637

This means that Aluminum is the limiting reagent. (We are working with 0.9637 moles of Aluminum.)

Step 4: Find amount of product formed

We can use the molar ratio of the balanced equation again to find how much AlH3 is made. The coefficient of Al is the same as the coefficient of AlH3. This means that equal no. if moles are made in the reaction.

This means that 0.9637 moles of Aluminum Hydride is formed in this reaction.

Step 5: Convert back to mass in grams

Now we just need to convert the no. moles back to mass using the same formula:

mass = no. moles x Molar Mass

m = 0.9637 x (26.98 + 3 x 1.01)

m = 0.9637 x 30.01

m = 28.92g (4.s.f.)

Hope this helped!

Answer:

true

Explanation:

Answer: 257.23

Explanation:

Answer:

12.6 g

Explanation:

Step 1: Write the balanced decomposition reaction

2 Fe₂O₃ ⇒ 4 Fe + 3 O₂

Step 2: Calculate the moles corresponding to 18.0 g of Fe₂O₃

The molar mass of Fe₂O₃ is 159.69 g/mol.

18.0 g × 1 mol/159.69 g = 0.113 mol

Step 3: Calculate the moles of Fe formed from 0.113 moles of Fe₂O₃

The molar ratio of Fe₂O₃ to Fe is 2:4. The moles of Fe formed are 4/2 × 0.113 mol = 0.226 mol

Step 4: Calculate the mass corresponding to 0.226 moles of Fe

The molar mass of Fe is 55.85 g/mol.

0.226 mol × 55.85 g/mol = 12.6 g

Answer:increase In kinetic energy of molecules

Explanation:increase in kinetic energy of molecules

When there is an increase in temperature of a gas in an enclosed container, the pressure will also increase due to the increase in the kinetic energy.

Temperature and pressure of gas is directly proportional to each other.

When the temperature of the gas increases, then the kinetic energy of the gas molecules are also increases. Due to increase in the velocity of gas molecules they will collide with each other as a result of which pressure of the gas is aslo increases.

Hence due to increase in kinetic energy, pressure increases.

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Answer: 39.948 grams

Explanation:

The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Argon, or 39.948 grams

Answer:

See Explanation

Explanation:

From Gay-Lussac's law of combining volumes;

Equation of the reaction; 2H2(g)  + O2(g) -------> 2H2O(g)

Ratio of volumes;              2           :    1                :    2

Initial volumes;                  500cm^3   500cm^3       0 cm^3

Reacting volumes;          500cm^3    250cm^3      500cm^3

Final Volumes;                0 cm^3        250 cm^3     500 cm^3

We can easily see from the table that the limiting reactant is oxygen.

Hence, the mass of water formed is obtained from;

1 mole of gaseous water occupies 22400 cm^3

x moles of water occupies 500cm^3

x = 500cm^3 * 1 mole/22400 cm^3

x = 0.022 moles of water

Mass of water = 0.022 moles of water * 18 g/mol

Mass of water = 0.396 g

As the bodies present in the gravitational force of sun, so it is appropriate to describe the sun and its celestial bodies as system.

Celestial bodies are those objects which are present in the space not in the land.

In the space all the planets are present in their orbitals under the gravitational force of the sun and do the motion around the sun, because of that force planets are present in the orderly arrangement. Because of the revolution of the earth around the sun, seasons will change on the earth.

Hence, it is appropriate to describe the sun and its celestial bodies as system.

To know more about celestial bodies, visit the below link:

https://brainly.com/question/3735999

Answer:

See Explanation

Explanation:

Let us closely consider the electronic configuration of manganese atom, Manganese II ion and manganese III ion. This will give a clue of the answer.

Manganese: [Ar] 3d5 4s2

Manganese II: [Ar] 3d5

Manganese III: [Ar] 3d4

Now, let us remember that the d orbital contains a maximum of ten electrons. Hence, the electronic configuration of Mn^2+, [Ar] 3d5 reflects a half filled d- orbital which is known to be unusually stable(half-filled orbitals are known to possess unusual stability just as fully filled orbitals do).

The same can not be said about Mn^3+. Hence, Mn^2+ is more stable than Mn^3+.

Answer:

48 mph

Explanation:

divide time by distance - 20/25 = .8 miles per minute, multiple by 60 to get mph

Answer:

Modern periodic table has eighteen (18) vertical columns. These are called groups

Balanced chemical reaction: 2KClO₃ → 2KCl + 3O₂.

Potassium is metal from first group of Periodic table of elements, it has always oxidation number in compound +1.

Chlorine in the reactant state has oxidation number +5 (+1 + x + 3 · (-2) = 0) and it is reduced to -1 (+1 + x = 0) in the product state.

Oxygen in the reactant state has oxidation number -2 (+1 + 5 + 3 · x = 0) and it is oxidized to 0 (in molecule of oxygen) in the product state.

Consider this reaction and answer the questions:

             Upper K upper C l upper O subscript 3 right arrow upper K upper C l plus upper O subscript 2.

What is the oxidation number of chlorine in the reactant state?

+5

What is the oxidation number of oxygen in the reactant state?

-2

What is the oxidation number of potassium in the reactant state?  

+1

What is the oxidation number of chlorine in the product state?

What is the oxidation number of oxygen in the product state?

What is the oxidation number of potassium in the product state?

Answer:

okkkkk

Explanation:

the balanced equation is

2NaBr +Cl2 =2NaCl + Br2

can you mark me as a brainliest

Answer:

cell :—

•They lack a well-defined nucleus, have a nucleoid instead.

•Usually have double-stranded, circular DNA.

•Do not have mitochondria.

Eukaryotic cell :—

•Have a well-defined nucleus enclosed in the nuclear membrane.

•Have a linear double-stranded nucleus.

•Mitochondria are present.

Answer: Steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a sign of chemical change.

Explanation:

A change that brings change in chemical composition of a substance is called a chemical change.

For example, Steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a chemical change.

This is because steel wool is mostly made up of iron and when iron becomes wet then in the presence of air it gets oxidized and therefore, it gets corroded.

This corrosion appears as reddish color of steel wool and it represents a chemical change has occurred in the steel wool.

Thus, we can conclude that steel wool turns from a gray color to a reddish color after it gets wet and then sits on a counter is a sign of chemical change.

Explanation:

[tex]XCl _{2(aq)} + 2AgNO _{3(aq)}→X(NO _{3}) _{2(aq)} +2 AgCl _{(s)}[/tex]

Answer:

[tex]XCl2(aq) + 2AgNO3(aq) --------> X(NO3)2(aq) + 2AgCl(s)[/tex]

Explanation:

The rule guiding he balancing of reaction equations is that the number of atoms of each element on both sides of the reaction equation must be the same.

In order to balance this equation, this rule must be applied. The balanced reaction equation therefore becomes;

XCl2(aq) + 2AgNO3(aq) --------> X(NO3)2(aq) + 2AgCl(s)

We can see by conducting an atom count that the number of atoms of each element on both sides of reaction equation is the same hence the equation is balanced.

Answer:

Probably around 6 because the ph of hydrochloric acid is 3

Explanation:

Answer:

O titanium, Ti

Explanation:

Answer: The new pressure of the gas at this volume is 10 atm.

Explanation:

Given: [tex]V_{1}[/tex] = 250 mL,        [tex]P_{1}[/tex] = 1.00 atm

[tex]V_{2}[/tex] = 25.0 mL,          [tex]P_{2}[/tex] = ?

According to Boyle's law, at constant temperature the pressure of an ideal gas is inversely proportional to volume.

Therefore, formula used is as follows.

[tex]P_{1}V_{1} = P_{2}V_{2}[/tex]

Substitute the values into above formula as follows.

[tex]P_{1}V_{1} = P_{2}V_{2}\\1.00 atm \times 250.0 mL = P_{2} \times 25.0 mL\\P_{2} = 10 atm[/tex]

Thus, we can conclude that the new pressure of the gas at this volume is 10 atm.

Answer:

Lava flows are streams of molten rock that pour or ooze from an erupting vent. Lava is erupted during either nonexplosive activity or explosive lava fountains. ... But when basalt lava flows are confined within a channel or lava tube on a steep slope, the main body of the flow can reach velocities >30 km/h (19 mph).

Explanation:

Answer:

a because it has a 2 and 3 in ot like it says in the question

Answer:

Renewable energy is energy from sources that are naturally replenishing but flow-limited; renewable resources are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. The major types of renewable energy sources are. Biomass. Wood and wood waste.

Explanation:

Answer:

A renewable resource is one that can be used repeatedly and does not run out because it is naturally replaced.

Explanation:

Explanation:

Your chemical equation should look like this:

Li3PO4 + AlF3 --> 3LiF + AlPO4

This is the balanced equation for a double-displacement reaction

Answer:

The astenosphere is located below the lithosphere

The mantle is composed of silicate material

Explanation:

The Earth has several different layers, and they can be presented in two different manners, depending on their chemical composition and their physical properties. According to the chemical composition the Earth has three layers, crust, mantle, and core, while in accordance to the physical properties it has five, lithosphere, astenosphere, mesosphere, outer core, and inner core.

The astenosphere is the second layer from the top, and it lies just below the lithosphere. It is also the upper part of the mantle. The mantle is a layer that is largely composed of silicate material, mostly silicate molten rock. It can easily be seen from the volcanic activities that this layer is composed of silicate material because the magma is rich in it, and the magma comes from this layer.

Answer: The reactivity of group 1 elements increases as you go down the group because: the atoms become larger. the outer electron becomes further from the nucleus. the force of attraction between the nucleus and the outer electron decreases.